Ments



(No Model.)

C. A. RANDALL.

TBLEPHONIG RELAY AND RBPBATER.

No. 250,283. Patented Nov. 29,1881.`

J, lwven't'oW n u Char-les JfHanc-lal maw@ 26 2 BH UNrTED STATES PATENT OFFICE.

CHARLES A. RANDALL, OF NEV YORK, N. Y., ASSIGNOR, BY MESNE ASSIGN- MENTS, TO THE RANDALL TELEPHONE MANUFACTURING COMPANY, OF

NEW YORK.

TELEPHONIC RELAY AND REPEATER.

SPECIFICATION forming part of Letters Patent No. 250,283, dated November 29, 1881.

' Application led December 23, 1880. (No model.)

To all whom it may concern Be it known that I, GHAELEs A. RANDALL, a citizen of the United States, residing at New York, in the county of New York and State of New York, have invented new and useful Improvements in Telephonie Relays and Repeaters, of which the following is a specification.

This invention relates to certain improvements in telephonie apparatus shown and deto scribed in Letters Patent granted to me ou the 30th day of November, 1880, and numbered, respectively, 235,019 and 235,020.

It has for its objects, first, the construction of a telephonic'relay or repeater of increased A.power as compared with those heretofore known, whereby main-line currents or impulses of electricity may be utilized and assisted to a high degree, and for producing` positive effects vat given points; and, second, to gather up and zo transfer to a second circuit the effect of the vibrations, however slight, of a diaphragm when acted upon by varyin g attractions or power of au electro magnet or magnets under theinfiuence of currents or impulses of electricity cor- 2 5 responding, in a greater or less degree, to the air-vibrations produced by sounds.

In the accompanying drawings, Figure l is a View, mainly in section, of a telephone receiving or relay apparatus constructed according to my invention; and Figs. 2 and 3 are similar views of modilications thereof.

In Fig. l'the letterA designates the casing of a telephone apparatus constructed as described in my Letters Patent No. 235,021.

3 5 B is a non-magnetic diaphragm, dampened and secured in any convenient manner. The diaphragm is provided with a centrally-projectin g soft-iron stud, C, which serves as a movable core for a fixed helix, D, the terminals of 4o which are connected respectively with screw posts c e at the end of the tubular case. One of these screw-posts is intended to be connected with the main-line wire and the other with the ground, or it may be used intermediately between the terminals of the main line.

An electro-magnet, E, is arranged within the tubular case, behind the helix D, and the terminals of the helix of this magnet are connect- `in lieu ot the magnet E.

ed with screw-posts g g', and these posts are to be respectively connected withthe opposite 5o poles of a battery, as at H. The magnet Eis adjustable to and from the helix D and its core by means of a screw rod, I, screwed to the rear end of the core ot' said magnet and passing through the heads of the case, where a suitable adjusting-nut, j, is secured upon it, and a spring, k, surrounding said 4rod and bearing against the helix and the inner surface ofthe head of the case. The electro-magnet is polarized by the current of the battery with which its helix is connected, and when alternately positive and negative currents are sent over the line-Wire and the helix D the polarity ot` the movable core C is reversed with each nlternation ot' the current, so that it is alternately attracted and repelled by the magnet E, thus causing the diaphragm B to vibratein correspondence with the electric impulses over the line. A permanent magnet may be used Upon and surrounding the central portion of the diaphragm is arranged a small tube, K, which is partially filled with mercury or other yielding or elastic substance, 7c', upon which rests a carbon disk, L, having a shank, l, which passes loosely through a central opening in a cap-piece or lid, and which abuts against the stud O. The stud O is made of carbon or platinum, and is carried by a leaf-spring, P, the opposite end ot' which is fixed to a stationary support. Upon the back of the end of the spring P which carries the stud O bears aspiral spring, Q, held in position by a rigidly supported screw-pin, which is provided with a nut, q, above the spring, for the adjustment of the leaves ofthe same. The diaphragm is connected with one terminal, r, and the spring P with the other terminal, r, ofa'circuit,in which is included a telephone-receiver proper, R.

The letters e e' and magnet D indicate the irst or main-line circuit. The line r, points l O, line i", telephone R, and wires r, back to battery, indicate the second circuit.

The mercury or pliable or yielding substance serves as a verysensitivc cushion, upon which the carbon rests, and when the diaphragm B vibrates its slightest movement is transmitted to the said carbon, and thus the ei'ect ot' the vibration of the diaphragm is transmitted to the local receiver circuit.

By theusc of this combination of devicesat once simple, readily adjustable, and very sensitive-I have obtained more perfect results at the receiver without loss of power or loudness of tones than by any other apparatus I have known.

In the modification shown in Fig. 2, in lieu of the mercury as a cushion, I use a short section of elastic tubing, K, the periphery ot' which rests upon the center of the diaphragm, while upon the opposite side of the cushion rests a carbon block, L', which is connected to one terminal wire, i,of the local receiver circuit. Upon this carbon block bears a stud or point, m', of carbon or platinum, carried by a leaf-spring, n, the opposite end of which is secured to a lug, 0, projecting` from a rigid arm, O', which is carried at one end of a leaf-spring, u2, the opposite end of which is fixed to a rigid suppoi-t. A rigid arm, O2, carries an adjustingscrew, P, which bears upon the free end of the arm 0', and by means of which the pressure of the stud m upon the carbon block L may be regulated. The spring n leads to wire l2, which is the opposite terminal of the receivercircuit, the terminal l of which is connected with a carbon block, L. I nd the rubber cushion K to be a very sensitive transmitter of the vibrations ot' the diaphragm to the carbon, and by which minute variations of the magnetic action are taken up.

In the modification shown in Fig. 3 the variable resistance acted upon by the diaphragm consists ot'anumber of metal screws, S, mounted in adisk, T, ofnon-conducting material, and each having at its lower end a metal plug, s', upon which tits one end of a short elastic rubber tube, as at S. Each tube is filled with a finely-powdered conducting substance, preferably carbon and silver in about equal proportions, and has its lower end closed by a metal plug, as S2. I use iive of these Variable resistances, the bottom plugs ot1 all resting upon a plate, U, from the center ot' the under side of which projects a short stud, a, which is secured to the center of the diaphragm B, so that the entire surface of the plate has the same movement as the center of the diaphragm, and the variations ofpressurc are equal upon all the substances, which should, by turning the screws, be so adjusted as to be of equal tension or resistance, and then connected to a common couductor, fv, which forms one ot the terminals of either a local or main line battery circuit, the other terminaht, ot' which is connected to the plate U. This battery or local circuit should include a telephonie receiver, and the apparatus described acts as a relay. In a main line the apparatus is used as a repeater. By this modification I am enabled to obtain afull flow of current and great variation of the same withoutdan geroi separatin g the contact-points and breaking the circuit when operated by loud tones, as is the case with spring telephonie contact-points.

What I claim, and desire to secure by Letters Patent, is-

l. In a telephonie relay or repeater,the combination ofa main-line electro-magnet, an electro-magnet permanently magnetized by a local battery or a permanent magnet, a Vibrator or diaphragm, and a variable resistance, which is included in a second circuit (local or main) and controlled by the action of said magnets, substantially as specified.

2. The combination, with the diaphragm arranged for actuation by an electro-magnet, of a body of mercury contained in a receptacle Supported by the diaphragm, and a variable resistance having a movable conductor in contact with the mercury or other substance, substantially as and for the purposeu set forth.

In testimony whereof I have hereunto set my hand in the presence of two subscribing witnesses.

CHARLES ADAMS RANDALL.

Witnesses GEO. M. BAKER, J AMES A. RUTHERFORD. 

